!Magister Rollant:

Dire Wolves can be found in the northern Dion Hills, or in the south across the river west of Dion Castle and also on the Plains of Dion.

Since Kadif Werewolves can only be found on the Plains of Dion, you'll have to cross the river anyway.

Giant Mist Leeches can be found in the Cruma Marshlands.

Antidotes can be bought at any store.